Vaporizer for an Electronic Cigarette

ABSTRACT

A vaporizer for an electronic cigarette is fluidically connectable to a liquid store and electrically connectable to a power supply unit in the electronic cigarette. The vaporizer comprises at least one heating element connectable to the power supply unit, an absorbing structure comprising at least one channel configured to receive liquid from the liquid store and conduct the liquid to the at least one heating element, and a pair of electrical contacts. Each electrical contact is arranged about the sides of the at least one channel. The electrical contacts are connectable to an electrical control circuitry when arranged in the electronic cigarette, and the electrical contacts are configured to establish a closed circuit and enable a supply of power to the at least one heating element only when liquid is present in the at least one channel.

FIELD OF THE INVENTION

The present invention relates to an electronic cigarette as well as to avaporizer for an electronic cigarette.

BACKGROUND OF THE INVENTION

The term electronic cigarette, or e-cigarette, is usually applied to ahandheld electronic device that simulates the feeling or experience ofsmoking tobacco in a traditional cigarette. Common e-cigarettes work byheating an aerosol-generating liquid to generate the aerosol that formsa vapor, which is then inhaled by the user.

Accordingly, using e-cigarettes is also sometimes referred to as“vaping”. The aerosol-generating liquid in the electronic cigaretteusually comprises nicotine, propylene glycol, glycerin and flavorings.The aerosol-generating liquid is sometimes also designated as “e-liquid”or simply as “liquid”, for short.

Typical e-cigarette vaporizers, i.e. systems or sub-systems forvaporizing the liquid, utilize a cotton wick and coil system to producevapor from liquid stored in a capsule or tank. When a user operates thee-cigarette, liquid that has soaked into the wick is heated by the coil,producing a vapor, which may then be inhaled.

However, there is a need to prevent the wick from being heated whencontaining an insufficient amount of liquid. Overheating a dry wick candeteriorate the taste of the vapor.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide a vaporizer for an electronic cigarette that reduces oreliminates the possibility of receiving a dry hit from an electroniccigarette, that is, of inhaling heated air, in which no e-liquid vaporor not enough e-liquid vapor is present. It is also an object of thepresent invention to provide a corresponding electronic cigarette.

The above objects are solved at least by the independent claims. Furtherembodiments, refinements, or upgrades are set out in the dependentclaims as well as in the following description and the drawings.

It is also advantageous to achieve a predetermined and constant feed ofliquid to the heater as this ensures that the temperature of the heaterremains constant. If there is a lack of liquid present in the thermalproximity of the heater, the heater temperature tends to increase andthere is a risk of overheating the liquid. In other cases, liquidprojections may be formed if there is an excess of liquid at the heater,and when the liquid enters a boiling stage rather than a vaporizationstage.

At the same time, it is desirable to ensure a high vapor volume. This isachieved by a relatively large vaporization surface and sufficientheater temperature.

The invention provides, according to a first aspect, a vaporizer for anelectronic cigarette, the vaporizer being fluidically connectable to aliquid store and electrically connectable to a power supply unit in anelectronic cigarette, the vaporizer comprising:

at least one heating element being connectable to the power supply unit,

an absorbing structure comprising at least one channel configured toreceive liquid from the liquid store and conduct the liquid to the atleast one heating element,

a pair of electrical contacts arranged about the sides of said at leastone channel,

wherein the electrical contacts are connectable to an electrical controlcircuitry when arranged in the electronic cigarette and wherein theelectrical contacts are configured to establish a closed circuit andenable a power supply to the at least one heating element only whenliquid is present in the at least one channel.

In the present context, fluidically connected means that a fluid canmove between the two parts of elements thus connected.

Preferably, the pair of electrical contacts is arranged at oppositesides of the at least one channel, in particular at or in walls of theat least one channel facing each other.

In some advantageous embodiments, variants, or refinements ofembodiments, the electrical contacts are located in the walls of the atleast one channel, and preferably located on each side of the at leastone channel side by side (or facing one another) in the horizontalplane. The horizontal plane shall be understood to be perpendicular to alongitudinal direction of the electronic cigarette.

In some advantageous embodiments, variants, or refinements ofembodiments, the electrical contacts are provided at the end of the atleast one channel, in particular at a radially outer end with respect toa longitudinal axis of the electronic cigarette and/or at an end closerto the radial or lateral exterior of the electronic cigarette than toits interior. This is especially advantageous if the liquid is providedto the at least one channel by a central supply channel such as a liquidconduit arranged in the center of the electronic cigarette, i.e. at theother, radially inner end of the at least one channel. In this way, theelectrical contacts are located at a position that has the highestlikelihood of becoming dry and becoming dry first, i.e. at the mostdistal point from the central supply channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the electrical contacts are deposited in the at least onechannel, preferably printed in the channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one channel is open in a directionperpendicular to a capillary flow direction within the at least onechannel. In this way, the liquid can be transported along the channeland can, once evaporated, leave the channel in said perpendiculardirection, for example towards an inhaling user.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one channel is a microfluidic channel.

In particular, the microfluidic channels may be nanoscale microfluidicchannels with width and/or depth of smaller than 1 micrometers,preferably between 10 nanometers and 850 nanometers. The absorbingstructure may comprise a plurality of microfluidic channels.

In some advantageous embodiments, variants, or refinements ofembodiments, the microfluidic channels of each of the at least onechannel are formed by a network of channels, preferably by at least twochannels running in parallel and separated by separations. Theseparations may have a linear shape in the longitudinal direction of thechannel.

In some advantageous embodiments, variants, or refinements ofembodiments, the microfluidic channels of each of the at least onechannel comprise a plurality of protrusions.

Providing microfluidic channels in the at least one channel limits theeffective cross-sectional flow area of the corresponding channel. Thismay increase the capillarity force and thus the liquid flow without theneed for active pumping mechanisms or the like. The width of the channelcan also be increased such that a higher liquid flow can be achieved.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure is a planar substrate on which theat least one channel and the at least one heating element are arranged.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer further comprises a supply conduit configuredto connect to a liquid transfer element and draw liquid by capillaryaction into the at least one channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure is divided into segments, andwherein each segment comprises a separate channel thermally coupled to aseparate heating element. Each channel has an end connected to thesupply conduit, preferably a radially inner end.

In some advantageous embodiments, variants, or refinements ofembodiments, in each segment of the absorbing surface structure only asingle channel is formed. In some embodiments, there may be just asingle segment with just a single channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one channel has an elongated structure,preferably a winding structure.

The invention also provides, according to a second aspect, an electroniccigarette comprising the vaporizer according to any embodiment of thefirst aspect. The electronic cigarette may further comprise a powersupply unit and control circuitry, wherein the at least one heatingelement is controllable by the control circuitry such that power issupplied from the power supply unit to the at least one heating elementonly when there is liquid present in the at least one channel to whichthe at least one heating element is thermally coupled.

In some advantageous embodiments, variants, or refinements ofembodiments, the control circuitry further comprises at least oneswitch, wherein each switch is configured to sense a liquid present in acorresponding channel and to selectively activate a heating elementthermally coupled to that corresponding channel.

In some advantageous embodiments, variants, or refinements ofembodiments, each switch is configured to sense a change in capacitanceor resistance due to the amount of liquid present in the correspondingchannel in order to determine the liquid present in the correspondingchannel.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer comprises a plurality of channels and aplurality of heating elements. Each of the heating elements may beindividually controllable by the control circuitry.

According to a third aspect, the invention provides a vaporizer for anelectronic cigarette, comprising an absorbing structure and a pluralityof heating elements, the heating elements being connectable to a powersupply unit in the electronic cigarette, wherein the absorbing structureis divided into segments, and wherein each segment is thermally coupledto a separate heating element. In this way, a more redundant design isprovided and vapor can be generated more homogenously.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure comprises at least one channelconfigured to conduct liquid to the at least one heating element.

In some advantageous embodiments, variants, or refinements ofembodiments, each segment comprises a separate channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the channels are open in a direction perpendicular to acapillary flow direction within the at least one channel. In this way,the liquid can be transported along the channel and can, onceevaporated, leave the channel in said perpendicular direction, forexample towards an inhaling user.

In some advantageous embodiments, variants, or refinements ofembodiments, at least one of the at least one channel has a windingstructure. In this way, the channel has a larger volume with respect toits depth, and covers more of the surface it is arranged in.

In some advantageous embodiments, variants, or refinements ofembodiments, the power is supplied from the power supply unit to any ofthe plurality of heating elements only when liquid is present in acorresponding one of the at least one channel such that each segment(or, more precisely: the heating element for each segment) isindividually activated upon the condition that liquid is present in saidsegment.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer further comprises a pair of electricalcontacts arranged about the sides of at least one channel and configuredas an open loop of an electrical control circuit, and wherein theelectrical control circuit is closed when liquid is present in thechannel, such that the power supply to the corresponding heating elementis only enabled when liquid is present in a corresponding at least onechannel.

In some advantageous embodiments, variants, or refinements ofembodiments, the electrical contacts are provided at the end of the atleast one channel, in particular a radially outer end. In this way, thecontacts are located at a position that has the highest likelihood ofbecoming dry and becoming dry first, i.e. at the most distal point fromthe central supply channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer further comprises a supply conduit configuredto draw liquid from the liquid store (and conduct said liquid into atleast one channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the supply conduit is connectable to a liquid transferelement.

In some advantageous embodiments, variants, or refinements ofembodiments, microfluidic channels of each of the at least one channelare formed by a network of channels. Separations may be formed betweenthe channels that have a linear shape in the longitudinal direction ofthe channel. Providing microfluidic channels in the at least one channellimits the effective cross-sectional flow area of the correspondingchannel. This may increase the capillarity force and thus the liquidflow without the need for active pumping mechanisms or the like. Thewidth of the channel can also be increased such that a higher liquidflow can be achieved.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure has a first layer in which thechannels are arranged and a second layer (or: plane) which comprises atleast one heating element of the plurality of heating elements, andwhich preferably comprises all of the plurality of heating elements.

According to a fourth aspect, the invention provides an electroniccigarette comprising a vaporizer according to any embodiment of thevaporizer according to the third aspect of the invention. The electroniccigarette may further comprise a power supply unit and controlcircuitry, wherein the at least one heating element of the vaporizer iscontrollable by the control circuitry, and wherein the control circuitryis configured such that power is supplied from the power supply unit tothe at least one heating element only when there is liquid present in atleast one channel to which the at least one heating element is thermallycoupled.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure of the vaporizer comprises aplurality of segments, each connected to a separate heating element.Each of the heating elements may be individually controllable by thecontrol circuitry. Thus, a more precise and more adaptable control ofthe plurality of heating elements is provided.

According to a fifth aspect, the invention provides a cartridge for anelectronic cigarette, the cartridge comprising a liquid store and avaporizer, the vaporizer comprising at least one heating element and anabsorbing structure having at least one channel fluidically connected tothe liquid store by a supply conduit, at least one channel being open ina direction perpendicular to a capillary flow direction within the atleast one channel, and wherein the at least one channel is configured toconduct liquid from the liquid store to the at least one heatingelement.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure is divided into segments. Eachsegment may comprise a separate channel and each segment may bethermally coupled to a separate heating element. Thus, a more preciseand more adaptable control of the plurality of heating elements isprovided.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer is formed on a substrate, and the at leastone channel is formed on a first side thereof. The at least one heatingelement may be formed on the second surface thereof. The substrate withthe channels may be formed in a sintering mold. In further advantageousvariants, the substrate comprises a porous ceramic material.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one heating element is arranged on the sameside as the at least one channel, and is preferably arranged at a bottomportion of the channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer has a planar shape. Thus, the vaporizer mayhave a small footprint and may be insertable into a variety ofelectronic cigarettes.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one heating element is shaped as a track andis aligned with the at least one channel. In other words, the at leastone heating element and the corresponding at least one channel may besuperposed. In this way, the heating element is adapted to optimallytransfer heat to the liquid arranged within the corresponding at leastone channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the bottom of the at least one channel is coated,preferably by an impervious coating such as a vitreous glazing. Thecoating improves or ensures the impermeability of the channels such thatliquid is not soaked up into e.g. a ceramic substrate in which the atleast one channel is formed. In this way, a reduction in the capillaryforce may be prevented.

In some advantageous embodiments, variants, or refinements ofembodiments, the supply conduit is configured to draw and transferliquid by capillary action into the at least one channel.

In some advantageous embodiments, variants, or refinements ofembodiments, the supply conduit is elongated and has a first end inconnection with the vaporizer and a second end in the liquid store.

In some advantageous embodiments, variants, or refinements ofembodiments, the vaporizer further comprises a pair of electricalcontacts arranged about the sides of said at least one channel, whereinthe electrical contacts form part of an electrical control circuit whenthe cartridge is arranged in an electronic cigarette, and wherein theelectrical contacts are configured to establish a closed circuit andenable a power supply to the at least one heating element only whenliquid is present in the at least one channel. The electrical contactsmay be configured as (part of) an open loop of an electrical controlcircuit, to be closed by the presence of the liquid. The open circuit tobe closed by the presence of the liquid may also be designated as a“sensing circuit”.

In some advantageous embodiments, variants, or refinements ofembodiments, the cartridge further comprises a first electrical powercircuit connected to the electrical contacts and a second electricalpower circuit connected to the at least one heating element. At leastone negative terminal of the first electrical power circuit may bearranged on an outer circumference of the cartridge. The electricalcontacts and the power circuit to the at least one heating element mayhave a common negative terminal. This reduces the number of terminalcontacts arranged on the cartridge. For example, the heating elementsmay all be connected to a ring-shaped electrical terminal. The positiveterminals (electrical contact points) may be separate for each channel,while the negative terminal for the sensing circuits and the powercircuit to the heating element can be common.

In some advantageous embodiments, variants, or refinements ofembodiments, a terminal end (preferably the positive terminal end) of asensing circuit is arranged on a side of the substrate, and arranged tobe connected to the cartridge seating on an electronic cigarette.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one channel is configured to transfer theliquid by capillary action along its entire length.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing surface may comprise a plurality ofmicrofluidic channels.

According to a sixth aspect, the invention provides an electroniccigarette comprising a cartridge seating, a power supply unit and acontrol circuitry.

The cartridge seating may comprise a first pair of electrical terminalsconfigured to power at least one heating element and a second pair ofelectrical terminals configured to establish at least one controlcircuit. The control circuitry comprises a controller configured todetect an electrical parameter (such as capacitance or resistance) ofthe at least one control circuit and control the supply of power to theat least one heating element such that power is supplied to the at leastone heating element only when the detected electrical parameter iswithin a predefined parameter range. For example, detecting anelectrical parameter may comprise measuring a value of the electricalparameter or otherwise determining whether the electrical parameter isin a predefined range. In some variants, if an electrical current flowsthrough the at least one control circuit, this can be considered adetecting that the resistance of the at least one control circuit is ina predefined value range, i.e. a range that allows the conduction ofelectrical current.

According to a seventh aspect, the invention provides a method ofmanufacturing the vaporizer according to any embodiment of the first orthe third aspect or of manufacturing the cartridge according to anembodiment of the fifth aspect, the method comprising the steps of:

-   -   providing a planar substrate with recesses formed as channels,    -   positioning electrical contact plates at a predetermined        position in relation to the channels,    -   depositing a resistive heating element onto the planar        substrate.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one heating element is deposited in therecesses, preferably by printing (additive manufacturing).

Furthermore, the invention provides, according to an eighth aspect, avaporizer for an electronic cigarette, the vaporizer comprising a liquidtransfer element, an absorbing structure and at least one heatingelement, wherein the liquid transfer element is configured for beingfluidically connected to a liquid store and for transferring liquid fromthe liquid store to the absorbing structure, and wherein the absorbingstructure comprises at least one channel configured to conduct liquidto, through, or over, the at least one heating element.

A liquid transfer element may be a passive element, for example, a wicksuch as a cotton wick, but may also be realized as an active elementsuch as comprising, or consisting of, a pump such as a micropump. Theliquid store may be permanently connected to the liquid transfer elementor may be part of a replaceable consumable such as a capsule, acartridge and/or the like.

The absorbing structure may preferably be formed as an absorbing surfacestructure. The term “absorbing surface structure” may in particulardesignate a structure which is open to the surroundings or to a cavityand which is configured to absorb liquid which has been transported tothe absorbing surface structure. The absorbing may in particular beperformed by capillary action or by other physical and/or chemicalprocesses. The absorbing surface structure may be located at the end ofa body member of the electronic cigarette. In particular, the absorbingsurface structure may be open to a vapor chamber or cavity in whichvaporized e-liquid is temporarily stored before being inhaled by theuser.

The at least one heating element may be a single heating element or,preferably, a plurality of heating elements such as two or more heatingelements, three or more heating elements, four or more heating elementsor the like.

In some advantageous embodiments or refinements of embodiments, the atleast one channel is configured to draw liquid from the liquid transferelement by capillary action. It shall be understood that, in embodimentsor variants where liquid store is not permanently fluidly connected tothe liquid transfer element, this is only the case when the liquid storeis fluidly connected to the liquid transfer element. Drawing the liquid(or: e-liquid or aerosol-generating liquid) by capillary action is asimple, reliable, cheap and yet efficient way to draw the liquid fromthe liquid transfer element and thus, by proxy, from the liquid storewhen it is fluidly connected to the liquid transfer element.

In some advantageous embodiments or refinements of embodiments, the atleast one channel comprises a plurality of micro fluidic channels.

The micro fluidic channel may be created by providing columns or pegswithin the at least one channel, so that between the columns and/or pegsand the walls of the at least one channel the micro fluidic channels aredefined. Such micro fluid channels are especially suitable to generatethe capillary action for drawing the liquid from the liquid transferelement without any additional mechanical moving element, such as amicro pump, being present. The inventors have found that the applicationor principles from the field of micro fluidics within the vaporizeraccording to the above described aspects provides many surprisingadvantages.

Micro fluidics describes the manipulation of fluids at thesub-millimeter length scale and typically involves the design ofmicroscale channels to carry fluids. At this scale, the phenomenaaffecting the behavior of fluids are significantly different to those atlarger scales such as they are usually used in currently knownelectronic cigarettes. In particular, capillary forces are more dominantat the sub-millimeter scale, allowing fluids to move an opposition togravity without an additional driving force such as the one exerted by amicro pump or the like.

Accordingly, it is preferred that a width and/or a depth of at least oneof the plurality of micro fluidic channels for each of the at least onechannel, preferably of all of the micro fluidic channels of the at leastone channel, is smaller than 1 millimeter, for example smaller than 0.5millimeters.

In particular, the microfluidic channels may be nanoscale microfluidicchannels with width and/or depth of smaller than 1 micrometers,preferably between 10 nanometers and 850 nanometers.

Capillary action, which is also known as wicking, facilitates easymovement of fluids in a microscale system. The inventors have found thatthe properties of such microscale systems can be used to great advantagewithin electronic cigarettes as described herein. In particular, thedirection of the wicking action and the micro fluid system may becontrolled via tailored design of the absorbing structure generating thecapillary action, here in particular the micro fluidic channels. Forexample, structural symmetry of the walls of the micro fluidic channelsmay be used to induce a direction-dependent Laplace pressure (surfacetension) in the fluid to control its movement.

The micro fluidic channels may be manufactured using techniques such asthe projection of light through a customized mask onto a chemicallytreated surface with the resulting pattern than replicated in a rubbersubstrate. The absorbing structure, or at least the micro fluidicchannels, may also be produced on a body member by additivemanufacturing (3D printing). The micro fluidic channels may alsoadvantageously be manufactured from graphene. Thus, herein also a methodfor producing a vaporizer for an electronic cigarette according toembodiments of the eighth aspect of the present invention is provided.

In common electronic cigarettes, availability of liquid for heatingwithin proximity of a heating element (such as a heating resistor) maybe affected by such factors as device orientation and liquid level.Constant monitoring of these factors is possible but may be inconvenientfor the user of the electronic cigarette. Moreover, it is desired byusers to be as free as possible in the use of the electronic cigarettes.The use of the micro fluidic channels offers a method of manipulatingthe supply of liquid to the at least one heating element even when thevaporizer is in an orientation in which gravity would usually force theliquid away from the at least one heating element. As mentioned before,capillary action can overcome gravity and thus ensure that sufficientamounts of liquid are reaching and wetting at least one heating elementof the at least one heating element.

Preferably, the absorbing structure is configured such that, when theliquid is absorbed by the absorbing structure, it is spread outessentially two-dimensionally over the absorbing structure, for examplesuch that at least 50% of the absorbing structure are wetted by thee-liquid being absorbed, preferably more than 60%, more preferably morethan 70%, even more preferably more than 80%. To achieve this, eachchannel may be structured in a winding manner, or, in other words, eachchannel may be formed with a winding structure. Each channel may beshaped in such a way as to maximize the area it is covering andenclosing.

By using micro fluidic channels, this effect may be realized withoutincreasing the complexity or size of the vaporizer as compared to othersolutions. The at least one channel, which may also be designated as a“heating channel”, may preferably be shaped such as to cover anaccording large percentage of the absorbing structure.

In some advantageous embodiments or refinements of embodiments, themicro fluidic channels in each of the at least one channel are formed bya network of channels or by a plurality of protrusions (such as columnsor pegs), which limit the effective cross-sectional flow area of thecorresponding channel. As has been described in the foregoing, microfluidic channels can be formed in this way. Moreover, the plurality ofprotrusions may serve also in other functions, for example as electricalcontacts.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure has a first layer in which the atleast one channel is arranged and a second layer which comprises atleast one heating element. The at least one heating element may beembedded in the second layer.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure is divided into segments, forexample two or more segments, three or more segments, four or moresegments, five or more segments, six or more segments, seven or moresegments, eight or more segments, or the like. The number of segmentsmay be determined by factors including the required granularity of theheating control capabilities (as defined by e.g. a manufacturer), andany design constraints associated with the manufacture of microfluidicchannels.

More segments result in a more homogeneous distribution of the generatedvapor even if some of the heating elements are in a particular momentnot heating in order to avoid dry burning. Preferably, the segments areall of the same size and/or arranged in a rotational symmetry in orderto provide an even more homogeneous distribution of the generated vapor.

Preferably, the segments are formed as circle sectors (i.e. as portionsof a disk enclosed by two radii and an arc), more preferably asequally-sized circle sectors and/or arranged in such a way that all ofthe segments together form essentially a disk, wherein however theindividual segments are preferably thermally isolated from one another,e.g. by an insulating material or by a gap.

Optionally, each segment comprises a separate channel thermally coupled(e.g. physically connected) to a separate heating element, and each ofthese channels has an end connected to the liquid transfer element.Preferably, each segment is provided with at least one heating element.In this way, each segment acts as an independent vaporizing unit whichis preferably designed such that the corresponding heating elements ofeach segment only generate heat when there is e-liquid present at, or inthe proximity of, the corresponding heating elements. This furtherreduces the chances of dry hits since no dry hit occurs if at least oneof the segments is supplied with e-liquid at all times.

Preferably, the absorbing structure comprises a plurality of segmentswith each segment connected to a separate heating element, and whereineach of the heating elements is individually controllable by controlcircuitry. The control circuitry may be comprised in the vaporizer, orthe vaporizer may comprise electrical contacts for connecting to anexternal control circuitry (for example, in the main body of anelectronic cigarette) such that the control circuitry may control eachof the heating elements individually.

Advantageously, the individual segments are thermally isolated from oneanother. This contributes to each segment being individuallycontrollable, in particular heatable, to individually controllablygenerate vapor.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure is electrically conductive.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure comprises a metal, such asTitanium.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure comprises a ceramic material.

In some advantageous embodiments, variants, or refinements ofembodiments, the segments are manufactured from graphene and/oroxide-coated copper. These materials have favorable thermal conductivityvalues so that the segments transmit the heat produced by the heatingelements well.

In some advantageous embodiments, variants, or refinements ofembodiments, in each segment of the absorbing structure only a singlechannel is formed. The single channel may be formed with a windingstructure and/or such as to maximize the percentage of the area of thecorresponding segment that is covered by the channel.

Alternatively, the channels may be formed between the individualsegments and such as to separate the segments from one another.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one channel is open in a directionperpendicular to the capillary flow direction within the at least onechannel. In this way, the liquid can be transported along the channeland can, once evaporated, leave the channel in said perpendiculardirection, for example towards an inhaling user.

In some advantageous embodiments, variants, or refinements ofembodiments, the at least one channel has a winding structure, i.e. insuch a way that the liquid changes direction multiple times along eachrespective channel and such that multiple sections of the channel arearranged essentially (or completely) in parallel to one another, andpreferably such that the majority of the channel is comprised ofsections that are arranged essentially (or completely) in parallel toone another. In this way, a channel of comparatively large length can beprovided in a comparatively small area.

The invention also provides, according to a ninth aspect, an electroniccigarette comprising the vaporizer according to any embodiment of theeighth aspect of the present invention. The electronic cigarette mayfurther comprise a power supply unit and control circuitry, wherein theat least one heating element of the vaporizer is controllable by thecontrol circuitry.

The control circuitry is configured such that power is supplied from thepower supply unit to the at least one heating element only when there isliquid present in the at least one channel to which the at least oneheating element is thermally connected. In some variants, the controlcircuitry may be provided partially within the vaporizer.

The term “thermally connected” in this context may be understood to meanthat the heating element is configured to apply heat to thecorresponding channel such that the heating element is able to vaporizee-liquid contained in at least one section of the channel.

The electronic cigarette may, apart from the vaporizer, also comprise aliquid store for storing the liquid for transport, by the liquidtransfer element, to the absorbing structure, and may also comprise ahousing, a battery portion, a user interface and/or further functionalportions or circuits. The liquid store may also be part of thevaporizer.

In some advantageous embodiments, variants, or refinements ofembodiments, the absorbing structure of the vaporizer comprises aplurality of segments, each connected to a separate heating element, andeach of the heating elements is individually controllable by the controlcircuitry.

In some advantageous embodiments, variants, or refinements ofembodiments, the control circuitry of the electronic cigarette furthercomprises at least one switch, and preferably each switch is configuredto sense a liquid present in a corresponding one of the channels and toselectively activate a heating element thermally coupled (or: connected)to that corresponding channel.

In some advantageous embodiments, variants, or refinements ofembodiments, each switch is configured to sense a change in capacitancedue to the amount of liquid present in the corresponding channel inorder to sense the liquid present in the corresponding channel. In thesecases, it is advantageous if the electronic cigarette is used withelectrically non-conductive liquid.

In some advantageous embodiments, variants, or refinements ofembodiments, each switch comprises (or is connected to) a firstelectrical contact and a second electrical contact, and each switch isconfigured to be closed by the presence of an electrically conductiveliquid within the corresponding channel in order to sense the liquidpresent in the corresponding channel.

In some advantageous embodiments, variants, or refinements ofembodiments, each switch is located at the far end, with respect to thetransfer element, of the corresponding channel. This is especiallyadvantageous if the switch is configured to be directly triggered by thepresence of a sufficient amount of liquid at the switch itself.

In some advantageous embodiments, variants, or refinements ofembodiments, at least some, and preferably all, of the electricalcontacts for each channel have a linear shape and extend over aplurality of windings of the corresponding channel.

According to a tenth aspect, the invention further provides a use of avaporizer according to any embodiment of the first aspect, the thirdaspect, or the seventh aspect of the present invention or a use of acartridge according to any embodiment of the fifth aspect of the presentinvention, or of an electronic cigarette according to any embodiment ofthe second, fourth, sixth or ninth aspect of the present invention, withan electrically non-conductive e-liquid. In this case, the e-liquid canbe used to non-conductively change the capacitance between to electricalcontacts for controlling at least one heating element.

According to an eleventh aspect, the invention further provides a use ofa vaporizer according to any embodiment of the first aspect, the thirdaspect, or the seventh aspect of the present invention or a use of acartridge according to any embodiment of the fifth aspect of the presentinvention, or of an electronic cigarette according to any embodiment ofthe second, fourth, sixth or ninth aspect of the present invention, withan electrically conductive e-liquid. In this case, the e-liquid can beused to close an electrical circuit between to electrical contacts forclosing a switch for controlling at least one heating element.

According to a twelfth aspect, the invention further provides avaporizer for an electronic cigarette, the vaporizer comprising a liquidtransfer element configured for being fluidically connected to a liquidstore and for transferring liquid out of the liquid store when connectedto the liquid store, an absorbing structure comprising at least onechannel, the absorbing structure fluidically connected to the liquidtransfer element and configured to conduct liquid transferred by thetransfer element via the at least one channel towards, to, and/orthrough at least one heating element thermally coupled (or: connected)to the channel,

a power supply unit, and

control circuitry configured such that power is supplied from the powersupply unit to each heating element only when there is liquid present inthe channel to which the heating element is thermally coupled (or:connected).

Although many features have been described herein with respect to aparticular aspect of the invention, it will be understood that thefeatures may, if not explicitly contradictive, be in the same way orsimilarly included in embodiments of different aspects of the invention.Any embodiment of the invention may be an embodiment of not only one butalso of a plurality or even of all aspects of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in greater detail with reference toexemplary embodiments depicted in the drawings as appended.

The accompanying drawings are included to provide a furtherunderstanding of the present invention and are incorporated in andconstitute a part of this specification. The drawings illustrate theembodiments of the present invention and together with the descriptionserve to explain the principles of the invention. Other embodiments ofthe present invention and many of the intended advantages of the presentinvention will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 schematically illustrates an electronic cigarette according to anembodiment of the present invention;

FIG. 2 schematically illustrates a vaporizer according to an embodimentof the present invention;

FIG. 3 control circuitry of an electronic cigarette according to anembodiment of the present invention or of, or for use with, a vaporizeraccording to an embodiment of the present invention; and

FIG. 4 schematically illustrates a vaporizer according to anotherembodiment of the present invention;

FIG. 5 schematically illustrates a vaporizer according to yet anotherembodiment of the present invention;

FIG. 6 schematically illustrates a vaporizer according to still anotherembodiment of the present invention;

FIG. 7 schematically illustrates a vaporizer according to yet anotherembodiment of the present invention;

FIG. 8 schematically illustrates a cartridge according to yet anotherembodiment of the present invention; and

FIG. 9 schematically illustrates an electronic cigarette in combinationwith the cartridge according to FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. Generally, thisapplication is intended to cover any adaptations or variations of thespecific embodiments discussed herein.

FIG. 1 schematically illustrates an electronic cigarette 1000 accordingto an embodiment of the present invention. The electronic cigarette 1000comprises a main body portion 1001 and a mouthpiece portion 1002. Themain body portion 1001 comprises a power supply unit 70 and controlcircuitry 60 configured for controlling the supply of electrical powerfrom the power supply unit 70. The electronic cigarette 1000 furthercomprises a vaporizer 50, a liquid store 20 and a mouthpiece 30, throughwhich a user can inhale the generated vapor 90.

In an embodiment, the main body portion 1001 and the mouthpiece portion1002 may be removably connected to each other to provide access to arefillable liquid store 20 in the mouthpiece portion 1002. In such acase, the main body portion 1001 of the electronic cigarette 1000 maycomprise a vaporizer seating for a removable vaporizer.

In another embodiment, the main body portion 1001 can be provided with acartridge seating configured to receive a liquid cartridge with anintegrated vaporizer.

Hence, depending on the specific configuration of the electroniccigarette 1000, the liquid store 20 may be part of or configured as aseparate from the vaporizer 50; 150. FIGS. 1 and 2 a show an example ofa liquid cartridge with an integrated liquid store 20 and vaporizer 50,a structure often referred to as a “cartomizer”.

Depending on the specific variant of the vaporizer 50, the electroniccigarette 1000 and the vaporizer 50 may be configured for use withelectrically conductive liquid or for use with electricallynon-conductive liquid.

As illustrated in FIG. 2a to c , the vaporizer 50 comprises an absorbingstructure 10 and at least one heating element 12-1. The absorbingstructure 10 is configured to receive the liquid from the liquid store20 and transport it towards the at least one heating element 12-1.

The absorbing structure 10 can advantageously be of a planar substrate,and provided with a first side and a second side. In the electroniccigarette 1000, the first side is positioned towards a mouthpiece 30 andthe second side is positioned opposite the mouthpiece outlet.

The absorbing structure 10 can advantageously comprise a ceramicmaterial, such as a porous ceramic material. Other possible material maycomprise, or consist of, Graphene, Titanium, oxide-coated copper, or anyother suitable material. The absorbing surface 10 comprises at least onechannel 13-i and at least one supply conduit 13-S connected thereto. Thesupply conduit 13-S is thus configured to receive liquid from the liquidstore 20 and transfer the liquid into the at least one channel 13-i. Theat least one channel 13-i is configured such that the liquid is drawninto the at least one channel 13-i by capillary action.

As best seen in FIG. 2a , the absorbing structure 10, i.e. the firstside of the substrate may be open to a vaporization cavity 35 in adirection perpendicular to the at least one channel 13-i.

Optionally, as illustrated in the embodiment of FIG. 2a , a liquidtransfer element 40 (for example a wick such as a cotton wick) may befluidically connected to the liquid store 20, for example by immergingthe liquid transfer element 40 partially in the e-liquid in the liquidstore 20. The liquid transfer element 40 transfers liquid from theliquid store 20, for example by capillary action, to the absorbingstructure 10 of the vaporizer 50. The absorbing structure 10 interfaceswith the liquid transfer element 40 (e.g. a wick) in such a way thatliquid absorbed by the liquid transfer element 40 may be transferredonto the absorbing structure 10. Preferably, the liquid transfer element40 is in direct physical contact with the absorbing structure 10.

FIG. 2b ) shows a top view of the absorbing surface structure 10 in FIG.2a from the direction of the mouthpiece 30. The first side of theabsorbing surface structure 10 comprises a plurality of segments 11-1,11-2 . . . to 11-i. The segments 11-i may be formed as equally-formedsegments 11-i and have a joined shape corresponding to an atomizerseating in the main body portion 1001 of the electronic cigarette 1000.Each segment 11-i may be provided with at least one correspondingdedicated heating element 12-i (only the heating element 12-1 isschematically illustrated in FIG. 2c )), i.e. the corresponding heatingelement 12-i is arranged and configured to heat at least part of thecorresponding segment 11-i. In the origin of the radii of the segments11-i, a supply conduit 13-S fluidically connected to an opening 15 isarranged (see FIG. 2a ) through which the liquid from the liquid store20 is received and transferred to the at least one channel 13-i. Thus,the liquid from the liquid store 20 enters the vaporizer 50 through theopening 15.

The at least one channel 13-i is arranged, in the embodiment of FIG. 2,such that one channel is arranged in each individual segments 11-i ofthe absorbing surface structure 10.

The channels 13-i can be provided with a microfluidic shape, where atleast one channel 13-i is formed in the proximity of a heating element12-i which enables an efficient vaporization and can therefore avoidheating when there is either insufficient or an excessive amount liquidpresent in the proximity of the heating element 12-i.

To this effect, the effective cross-section of the at least one channel13-i is preferably provided with a dimension at a submillimeter scale.In an embodiment, the at least one channel has a width and/or depth ofsmaller than 1 micrometers, preferably between 10 nanometers and 850nanometers.

In one particular embodiment, if there is a single channel, theeffective cross-sectional area is the cross section of the individualchannel. The channel can thus alone be formed as a microfluidic channel.

As schematically illustrated in FIG. 2c , the effective cross-sectionalflow area is achieved by microscale structures 16-i provided within eachchannel 13-i such as to form microfluidic channels within each channel13-i. Preferably these structures are on the nanoscale level. Asillustrated in FIG. 2c , the microscale structures can be formed frommicroscale or nanoscale pegs or nanoscale columns 16-1. In anotherembodiment, as illustrated in FIG. 2d , the microscale structures areformed from longitudinal channel partitions 131, whereby a main channel13-i is separated into a group of side-by-side (preferably parallel)microscale or nanoscale channels 132.

In one and the same embodiment, when there is a plurality of channels13-i, different types of microscale structures may be formed indifferent channels 13-i, for example in one channel 13-i there may bepegs or columns 16-1 and in another one there may be longitudinalchannel partitions 131. This may be advantageous if the electroniccigarette 1000 is usable with a variety of different types of liquidsthat may have different viscosity, surface tension and the like, so thatdifferent microscale structures are adapted for different types ofliquids.

The at least one heating element 12-i is configured to vaporize theliquid to generate vapor. The heating elements 12-i may, for example, berealized as an Ohmic resistance heater.

The absorbing structure 10 may have a first side in which the at leastone channel 13-i is arranged and a second side which comprises the atleast one heating element 12-i. The substrate may comprise a single anduniform material and whereby the first side and the second side mayrefer to different positions or planes in the substrate.

Optionally, the absorbing structure 10 may comprise a plurality oflayers, wherein the at least one channel is arranged in a first layerand the heater in a second layer.

The at least one heating element 12-i is preferably embedded in thesecond side or the second layer of the substrate. Thus, for example, thefirst layer may form walls of the channels 13-i; and the second layer,which is heatable by the at least one heating element 12-i, may form afloor of the channels 13-i. Preferably, for each channel 13-i at leastone heating element 12-i is provided. There may also be a plurality ofheating elements 12-i provided for each channel 13-i.

The at least one heating element 12-i may be disposed within thechannels 13-i and/or embedded within a wall or a floor (or, in somevariants, in a ceiling) of the respective channel 13-i so that, when therespective heating element is activated the liquid contained within thechannel 13-i (or within a part of the channel 13-i) is vaporized.

Alternatively or additionally, the absorbing structure 10 may bethermally conductive such that they can dissipate heat from the at leastone heating element 12-i. In such variants, the segments 11-i maycomprise, or consist of, a thermally conductive material such asgraphene or oxide-coated copper which is able to transmit the heatgenerated by the respective heating element 12-i to the respectivechannel 13-i.

In another preferred embodiment, the heating element 12-i is positionedon the second side of the planar substrate. The channel 13-i is providedon the first side of the planar substrate (top side) and the at leastone heating element 12-i is provided on the opposite second side of theplanar substrate. The at least one heating element 12-i can be shaped asa track and is aligned with the channel 13-l present in the samesegment. This enables a maximum amount of heat to be transferred to theliquid in the conduit.

In order to control the at least one heating element 12-i to beindividually active or inactive, control circuitry 60 is provided forindividually controlling the heating elements 12-i. The controlcircuitry 60 may be arranged at least partially in the vaporizer 50;150. Such control circuitry 60 is schematically illustrated in FIG. 3.The control circuitry 60 comprises a plurality of sensing circuits,connected to a plurality of heating elements 12-1, a main power switch62 and electrical contacts 14-1 to 14-8.

In particular, the control circuitry 60 may be arranged and configuredto selectively open and close individual electrical circuits connectingeach of the heating elements 12-i to a power supply unit 70 of theelectronic cigarette 1000, as will be described in the following.

As seen in FIG. 3, each individual heating element 12-i (of which only12-1, 12-2 and 12-8 are shown for reasons of conciseness) is providedwith its on switch 14-1 a, 14-2 a, 14-8 a (or: 14-ia in general) bywhich the respective heating element 12-i may be switched on or off(i.e. provided with electrical power or cut off from electrical power)individually.

The control circuitry 60 may comprise, or be connected or connectableto, a user interface 64 with which a user may input control signals intothe electronic cigarette 1000 and/or receive output signals from theelectronic cigarette 1000. For example, the user interface 64 may in asimple case comprise only a main switch (on/off switch). It may alsocomprise one or more further control elements (buttons, sliders,switches), visual indicators

(LEDs, displays), acoustic indicators (loudspeakers) and/or the like.

The main switch 62 (or: general on/off switch) may be provided forcutting the electric power by the power supply unit 70 off completelyfrom all of the heating elements 12-i. Said main switch 62 may becoupled to an on/off button e.g. in a user interface 64 of theelectronic cigarette 1000 and/or to a microcontroller or othercontrolling circuit.

In other words, in preferable variants and embodiments, as long as themain switch 62 is closed, each heating element 12-i that is currentlythermally connected to a liquid to generate vapor will be active, andeach heating element 12-i that is currently not thermally connected toany liquid will be inactive, wherein “thermally connected to a liquid”herein means that a sufficient amount of the heat generated by theheating element 12-i can reach a liquid to vaporize it.

Hence, one of the main ideas of the present disclosure is that onlythose switches 14-ia are closed only when liquid is present in the atleast one channel 13-i. The control circuitry can thus be configured toonly enable the supply of power to the heating element when liquid ispresent in the channel to which the heater is thermally connected.

Control signals for controlling the switches 14-ia may originate from alarge number of diverse sources such as microcontrollers, sensors and soon which may be part of the electronic cigarette 1000 or of thevaporizer 50 in particular.

The presence of liquid in the channel is detected by separate sensingcircuits 15-i. As schematically shown with respect to FIG. 2c , theelectronic cigarette 1000 further comprises at least one sensing circuit15-i. In the embodiment where the vaporizer comprises a plurality ofchannels 13-i and a plurality of heating elements 12-i, a plurality ofsensing circuits 15-i is formed. The sensing circuit 15-i comprises afirst part which is located in the vaporizer (or consumable) and asecond part that is located in the main circuitry of the main body ofthe electronic cigarette.

The switches 14-ia (illustrated with switch 14-1 a of the first segment11-1) comprise a pair of electrodes or electrical contacts 14-1 b, 14-1c which are arranged at two opposed walls of the respective channel13-i. The volume of the respective channel 13-i between the electricalcontacts 14-1 b, 14-1 c may thus be designated as a detecting portion17-i of the channel 13-1. The detecting portions 17-i may span the wholechannel 13-i, i.e. the whole of the respective channel 13-i may beconfigured as a detecting portion 17-i, e.g. by the electrical contacts14-ib, 14-ic spanning the whole channel 13-i.

Preferably, the nanoscale structures 16-i are present at least in thedetecting portion 17-i of the respective channel 13-i, more preferablyat least from the opening 15 throughout at least the detecting portion17-i, most preferably from the opening 15 throughout the completechannel 13-i until its outer radial end. Thus, the capillary effectcreated by the nanoscale structure 16-i acts to draw liquid from theliquid transfer element 40 at least into the detection portion 17-i.

The detecting portion 17-i is preferably arranged at least halfway alongthe channel 13-i starting from the opening 15, more preferably at least60% along that way, even more preferably at least 80% along that way.The heating elements 12-i may be arranged to heat the liquid at least ina portion of a respective channel 13-i starting from the opening 15 andextending at least up to the detecting portion 17-i. In this way, thearrangement of the detecting portion 17-i (by the arrangement of therespective electrodes 14-1 b, 14-1 c) corresponds to a desiredtriggering amount (corresponding to a length along the channel 13-i) ofliquid to be present in the channel 13-i before the switches 14-i shallbe triggered to close and thus the heating elements 12-i be activated.

The triggering of the switches 14-i by the liquid may be performed byelectric conductivity sensing or by capacitive sensing. In the case ofelectric conductivity sensing, the liquid used with the vaporizer 50 andelectronic cigarette 1000 is a conductive liquid and the segments 11-ithemselves are electrically non-conductive. Thus, an electricalconnection between the electrical contacts 14-ib, 14-ic of each switch14-ia is only created when the electrically conductive liquid is presentbetween them and acts as a conductive bridge. Thus, the switch 14-iaacts as both a sensor and a switch at the same time.

Alternatively, the electrical connection between two electrical contacts14-ib, 14-ic may be detected, e.g. by a microcontroller, and the switch14-ia itself, which may be digitally controllable switch separate fromthe electrical contacts 14-ib, 14-ic, may be controlled by themicrocontroller to close or open accordingly, i.e. to close when (and aslong as) the electrical connection between the two electrical contacts14-ib, 14-ic is detected and to open when (and as long as) theelectrical connection between the two electrical contacts 14-ib, 14-icis not detected.

In the variants with electric conductivity sensing, it is preferred ifthe detecting portion 17-i is only a minor portion of the entire channel13-i, for example less than 30% of its length, less than 20% of itslength, less than 10% of its length or the like. Moreover, it ispreferred that said detecting portion 17-i is arranged towards the outerradial end of the channels 13-i, for example at least 50% along itslength starting from the opening 15, at least 60%, at least 70%, atleast 80%, at least 90% or the like. Then, due to the capillary effectcreated by the nanoscale structures 16-i, the closing of the switch14-ia by the liquid (or because of the presence of the liquid in thedetecting portion 17-i) indicates that the liquid is present in acorresponding percentage of the channel 13-i. The detecting portions17-i may advantageously provide a decentralized sensing capability ofthe vaporizer 50.

In other variants, the vaporizer 50 and electronic cigarette 1000 may beconfigured for use with an electrically non-conductive liquid. Theelectrical contacts 14-ib, 14-ic then act as capacitor plates and theliquid in between as a dielectric. The presence/absence of liquidbetween the electrical contacts 14-ib, 14-ic thus affects thecapacitance of the capacitor, which may be used to trigger thecorresponding switch 14-ia.

For example, a microcontroller of the electronic cigarette 1000 or ofthe vaporizer 50 in particular may monitor the capacitance of thecapacitor formed by the electrical contacts 14-ib, 14-ic and may causethe switches 14-i to open/close, respectively, when capacitance valuesto a specific side of a capacitance threshold value are detected.Preferably, the respective switches 14-i are closed (and stay closed)when, and as long as, a capacitance value larger than a threshold valueis detected and opened (and stay open) when, and as long as, acapacitance value smaller than a threshold value is detected, with thecase for a capacitance value being equal to the threshold value beingput to either side.

Other forms of capacity sensing of the presence/absence of liquid withinthe channels 13-i are possible, as will be described later.

FIG. 4 schematically show details of an absorbing surface structure 110according to vaporizer 150 according to another embodiment of thepresent invention. It should be understood that the vaporizer 150 may beused in an electronic cigarette 1000 that may otherwise be the same asdescribed with respect to FIG. 1, FIG. 2 and/or FIG. 3.

FIG. 4a schematically illustrates a top view of the absorbing surfacestructure from the direction of the mouthpiece 30 of an electroniccigarette 1000, in analogy to the illustration in FIG. 2b ).

In the absorbing surface structure 110 in the embodiment of FIG. 3, foursegments 111-1, 111-2, 111-3, 111-4 (hereafter also sometimescollectively designated as 111-i) are provided, each with at least oneheating element, and each with a single channel 113-i. The segments111-i are equally-sized and in the shape of a quarter of disk (circlesector with 90° angle). In the embodiment of FIG. 3, each channel 113-iis formed with a winding structure:

the liquid changes direction multiple times along each respectivechannel 113-i and multiple sections of each channel 113-i are arrangedessentially (or completely) in parallel to one another (and essentiallyperpendicular to the radial direction), and preferably the majority ofthe channel 113-i is comprised of sections that are arranged essentially(or completely) in parallel to one another.

Advantageously, the channel 113-i is tightly packed in each respectivesegment 111-i, for example such that at least 50% of the absorbingsurface structure 110 covered by the channels 113-i, preferably morethan 60%, more preferably more than 70%, even more preferably more than80%. In this way, a maximum amount of liquid can be held within eachchannel 113-i, and when each segment 111-i is heated, e.g. by arespective heating element having essentially (or exactly) the same formas the segment 111-i, a maximum amount of liquid is heatedsimultaneously.

FIG. 4b ) shows the structure of the channel 113-1 of the absorbingsurface structure 110 in more detail. The detecting portion 117-1 of thechannel 113-1 may be configured in any of the ways as has been describedin the foregoing for the detecting portions 17-i of the channels 13-i,in particular in any of the variants for use with electricallyconductive liquid (electrical conductivity sensing) or withnon-conducting liquid (capacitive sensing). Again, it is preferred eachdetecting portion 117-i is arranged towards the outer radial end of therespective channel 113-i, for example at least 50% along its lengthstarting from the opening 15, at least 60%, at least 70%, at least 80%,at least 90% or the like. Then, due to the capillary effect created bythe nanoscale structures 16-i, the closing of the switch 14-ia by theliquid (or because of the presence of the liquid in the detectingportion 117-i) means that the liquid is present in a correspondingpercentage of the channel 113-i.

Additionally or alternatively, the absorbing surface structure 110 maybe configured such that the detecting portions 117-i of the absorbingsurface structure 110 are arranged in the respectively outermost branchof each channel 113-i, or, in other words, in a portion of the channel113-i closest to the outer radial end of the absorbing surface structure110. It should be understood that the detecting portions 117-i may alsoextend over multiple branches of the respective channel 113-i or mayeven extend over the whole length of the channel 113-i. In any case, itis preferred (although not necessary) that the segments 111-i of theabsorbing surface structure 110 are arranged with rotational symmetry,in the present case with a rotational symmetry of C4 about a rotationalaxis located in the center of the absorbing surface structure 110,within the opening, and perpendicular to the disk of the absorbingsurface structure 110. Of course, any other number n of segments 111-imay be provided, and thus a corresponding Cn symmetry may apply.

FIG. 5 schematically illustrates a detail of a vaporizer according toyet another embodiment of the present invention. FIG. 5 a) shows thesame view as FIG. 4b ), i.e. a detail of one segment 211-1 out of aplurality of segments 211-i of an absorbing surface structure 210,wherein the segments 211-i are equally-sized and equally-structured andarranged with rotational symmetry. In FIG. 5 a), again n=4 segments witha C4 symmetry have been chosen as an example, with only one segment211-1 being shown.

In the embodiment of FIG. 5, the absorbing surface structure 210 of thevaporizer is formed with the same heating elements and the same channels113-i of winding structure as shown in, and discussed with respect to,FIG. 4. The difference in the embodiment of FIG. 5 is that there is nodetecting portion 117-i arranged within the channel 113-i, but that therespective detecting portion comprises the respective entire segment211-i. This is achieved by providing mesh-like and/or fan-likeelectrical contacts 214-1 b, 214-1 c which sandwich between them thelayer of the absorbing surface structure 210 comprising the channel113-1.

The fence-like and/or fan-like and/or mesh-like electrical contacts214-1 b, 214-1 c allow generated vapor to escape through the gapsbetween the bars, grids or braces of the fence-like and/or fan-likeand/or mesh-like electrical contacts 214-1 b, 214-c while also obtainingsufficient information about the presence of liquid throughout thesegment 211-i by capacitive sensing.

In this context, “fan-like” may mean that bars are arranged as connectedat a central point (e.g. the radial origin of a segment 211-1 as shownin FIG. 5) and extend radially outward from there.

“Fence-like” may indicate the presence of bars alternating with gaps,wherein the bars may be parallel to one another or arranged at an angleof less than 180° to one another, preferably of less than 90°, e.g. asshown in FIG. 5a ). The distances and/or gaps between each twoneighboring bars are preferably identical.

“Mesh-like” may indicate at least some braces crossing other braces suchas to form T-shaped junctions (e.g., as shown in FIG. 5a ) at the outerradial end of the segment 211-1) or cross-shaped junctions, for examplea plurality of braces forming a chess pattern.

The use of the electronic cigarette 1000 according to any of the hereindescribed embodiments or variants, comprising any of the hereindescribed embodiments of variants of the vaporizer 50; 150, may proceedas follow:

The liquid transfer element 40 is brought into contact with liquidstored in the liquid store 20. This may be performed during manufactureof the electronic cigarette 1000, or during assembly of the electroniccigarette 1000 by the user, for example when replacing a vaporizer 50;150 and/or when replacing a liquid store 20. For example, the liquidstore 20 may be comprised in a removable and disposable capsule, or thevaporizer 50; 150 may be a removable and disposable unit, whereas theliquid store 20 may be a refillable tank in the housing 80 of theelectronic cigarette 1000.

A user may turn on the electronic cigarette 1000, e.g. by manipulating abutton of the user interface 64 that operates the main switch 62. Invariants with a passive liquid transfer element 40 (such as a wick), theliquid transfer element 40 may already be saturated with liquid at thepoint. Alternatively, turning on the electronic cigarette 1000 may alsoactivate an active liquid transfer element 40 (such as a micropump) tostart transferring liquid from the liquid store 20 to the vaporizer 50;150.

By capillary action (due to the specific structure of the channels 13-i;113-i of the absorbing surface structure 10; 110; 210), the liquid isthen distributed by the channels 13-i; 113-i throughout the segments11-i; 111-i. It may happen that the liquid is at times distributedunevenly between the segments 11-i; 111-i such that some segments 11-i;111-i receive more liquid than others. The liquid enters the detectingportions 17-i; 117-i in the channels 13-i; 113-i and triggers, if theamount of liquid in a particular detecting portion 17-i; 117-i issufficient, a corresponding switch 14-ia so as to control (or: actuate,or: activate) a corresponding heating element 12-i to start heating thecorresponding segment 11-i; 111-i to generate vapor from the liquid byvaporizing it.

The amount being “sufficient” is determined by the design of thedetecting portions 17-i; 117-i and/or by the design of the controlcircuitry 60, for example by triggering threshold values for electricalconductivity and/or capacitance, by digital thresholds programmed into amicrocontroller and/or the like. The sufficient amount may, forinstance, be determined based on the amount per time that can bevaporized by the heating elements 12-i continuously.

If during this process at any point the amount of liquid in any of thedetecting portions 17-i; 117-i becomes too small, the correspondingswitch 14-ia are opened and heating by the corresponding heating element12-i ceases, just as in any of the detecting portions 17-i; 117-i inwhich the amount of liquid becomes sufficiently large, heating is(re-)started.

In the case that at any time in none of the detecting portions 17-i;117-i a sufficient amount of the liquid is present, a signal may beprovided to a user of the electronic cigarette 1000, for example via theuser interface 64. For example, a sound, a melody, or a spoken messagemay be played to the user, or an indicator LED may be active, or a textmessage may be displayed by a display of the user interface 64.

Thus, the electronic cigarette 1000 has improved liquid flow andincreased device component lifespan because of the targeted and preciseactivation/deactivation of heating elements 12-i. In particular, wickand battery lifespan are extended. Moreover, user satisfaction isimproved as the overall generation of vapor is more consistent and theoccurrence of “dry hits” is eliminated or at least reduced without theneed for an increased device size.

FIG. 6 schematically illustrates a detail of a vaporizer according toyet another embodiment of the present invention. FIG. 6 shows the sameview as FIG. 2b ), i.e. a top view of an absorbing structure 310 of avaporizer. The absorbing structure 310 comprises a single segment 311with a single (preferably microfluidic) channel 313. Along the sides ofthe channel 313, electrical contacts 14-1 b and 14-1 c are disposed ashas been described in the foregoing. In this variant, the channel 313 isformed as a straight line or track running through the center of theabsorbing structure 310, where the opening 15 is arranged, and beginningand ending at the radial outer ends of the absorbing structure 310.

The electrical contacts 14-1 b and 14-1 c correspond to a detectingportion 17-1 and are preferably arranged at one of the radial outer endsof the channel 313. As has been described in the foregoing, only whenthe presence of liquid is detected in the detecting portion 17-1, iselectrical power supplied to at least one heating element. In thisvariant, heating elements may be arranged at/in both branches of thechannel 313 extending to both sides from the opening 15.

Optionally, two pairs of electrical contacts 14-1 b and 14-1 c may bearranged, one at each opposite end of the channel 313, and each may beconfigured to detect the presence of liquid in a corresponding detectingportion for activating or deactivating a corresponding one of the twoheating elements.

FIG. 7 schematically illustrates a detail of a vaporizer according toyet another embodiment of the present invention. FIG. 7 shows the sameview as FIG. 6, i.e. a top view of an absorbing structure 410 of avaporizer. The absorbing structure 410 comprises is different from theabsorbing structure 310 of FIG. 6 in that a single channel 413 in theabsorbing structure 410 is formed not as a straight line but as awinding or multiply-turning curve. As has been described in theforegoing with respect to FIG. 6, at least one pair of electricalcontacts or two pairs of electrical contacts, at least one heatingelement or two heating elements and so on may be provided.

Compared to the channel 313 in FIG. 6, the channel 413 of FIG. 7 islarger even when the absorbing structure 410 of FIG. 7 has the same sizeas the absorbing structure 310 of FIG. 6. Thus, more liquid can bepresent within the absorbing structure 410 at the same time, and theamount of liquid that can be vaporized per time unit is increased.

FIG. 8 schematically illustrates a cartridge 55 according to yet anotherembodiment of the present invention. The cartridge 55 comprises avaporizer 50; 150 configured in any of the ways as described in theforegoing. The cartridge 55 also comprises a liquid store 20 for storinga liquid to be vaporized by the vaporizer 50. The liquid from the liquidstore 20 is transported, by a liquid transport element 40, to at leastone channel in the absorbing surface of the vaporizer 50; 150. Theliquid transport element 40 may be an active or a passive element. Oneexample for a passive element is an element which uses capillary forceto transport the liquid, e.g. a wick.

The vaporized liquid escapes from the one or more channels into a cavity35 into which outside air can enter via an air inlet 36. The cavity 35is connected or connectable to a mouthpiece 30 (not necessarily part ofthe cartridge 55) via at least one vapor flow tube 52. The at least onevapor flow tube 52 preferable traverses—in a fluidically isolatedmanner—the liquid store 20 so that a very compact design is achieved.

FIG. 9 schematically illustrates an electronic cigarette 1000 incombination with the cartridge 55 of FIG. 8 inserted therein. It isshown how the cavity 35 is, compared to the mouthpiece 30, at the distalend of the cartridge 55. Apart from the vaporizer being part of thecartridge 55, the electronic cigarette may have the same features as hasbeen described in the foregoing, in particular with respect to FIG. 1.

The cartridge 55 comprises electrical contacts for connecting to thecircuitry within the electronic cigarette 1000, in particular to thepower supply unit 70. Electrical terminals arranged at the cartridge 55are configured to be connected to corresponding electrical terminals ata cartridge seating of the electronic cigarette 1000.

The cartridge seating may comprise a first pair of electrical terminalsconfigured to power at least one heating element of the cartridge 55 anda second pair of electrical terminals configured to establish at leastone control circuit.

The control circuitry 60 of the electronic cigarette 1000 comprises thecontroller configured to detect an electrical parameter (such ascapacitance or resistance) of the at least one control circuit andcontrol the supply of power to the at least one heating element suchthat power is supplied to the at least one heating element only when thedetected electrical parameter is within a predefined parameter range.For example, detecting an electrical parameter may comprise measuring avalue of the electrical parameter or otherwise determining whether theelectrical parameter is in a predefined range. In some variants, if anelectrical current flows through the at least one control circuit, thiscan be considered a detecting that the resistance of the at least onecontrol circuit is in a predefined value range, i.e. a range that allowsthe conduction of electrical current.

Although specific embodiments of the invention are illustrated anddescribed herein, it will be appreciated by those of ordinary skill inthe art that a variety of alternate and/or equivalent implementationsexist. It should be appreciated that the exemplary embodiment orexemplary embodiments are examples only and are not intended to limitthe scope, applicability, or configuration in any way. Rather, theforegoing summary and detailed description will provide those skilled inthe art with a convenient road map for implementing at least oneexemplary embodiment, it being understood that various changes may bemade in the function and arrangement of elements described in anexemplary embodiment without departing from the scope as set forth inthe appended claims and their legal equivalents. Generally, thisapplication is intended to cover any adaptations or variations of thespecific embodiments discussed herein.

It will also be appreciated that in this document the terms “comprise”,“comprising”, “include”, “including”, “contain”, “containing”, “have”,“having”, and any variations thereof, are intended to be understood inan inclusive (i.e. non-exclusive) sense, such that the process, method,device, apparatus or system described herein is not limited to thosefeatures or parts or elements or steps recited but may include otherelements, features, parts or steps not expressly listed or inherent tosuch process, method, article, or apparatus. Furthermore, the terms “a”and “an” used herein are intended to be understood as meaning one ormore unless explicitly stated otherwise. Moreover, the terms “first”,“second”, “third”, etc. are used merely as labels, and are not intendedto impose numerical requirements on or to establish a certain ranking ofimportance of their objects.

LIST OF DRAWING SIGNS

-   10 absorbing structure-   11-i segments-   12 heating element-   13-S supply conduit-   13-i channel-   14-ia switch-   14-ib electrical contacts-   14-ic electrical contacts-   15 opening or liquid conduit-   15-i sensing circuit-   16-i microscale structures-   17-i detecting portions-   20 liquid store-   30 mouthpiece-   35 cavity-   36 air inlet-   40 liquid transfer element-   50 vaporizer-   52 vapor flow tube-   55 cartridge-   60 control circuitry-   62 main switch-   64 user interface-   70 power supply unit-   80 housing-   90 vapor-   110 absorbing structure-   111-1 segment-   113-i channel-   117-1 detecting portion-   150 vaporizer-   210 absorbing structure-   211-1 segment-   214-1 b electrical contact-   214-1 c electrical contact-   310 absorbing structure-   313 channel-   410 absorbing structure-   413 channel-   1000 electronic cigarette-   1001 body portion-   1002 mouthpiece portion

1. A vaporizer for an electronic cigarette, the vaporizer beingfluidically connectable to a liquid store and electrically connectableto a power supply unit in the electronic cigarette, the vaporizercomprising: at least one heating element being connectable to the powersupply unit, an absorbing structure comprising at least one channelconfigured to receive liquid from the liquid store and conduct theliquid to the at least one heating element, and a pair of electricalcontacts, each electrical contact of the pair of electrical contactsbeing arranged adjacent to a respective side of said at least onechannel, wherein the electrical contacts of the pair of electricalcontacts are connectable to an electrical control circuitry whenarranged in the electronic cigarette, and wherein the electricalcontacts are configured to establish a closed circuit and enable asupply of power to the at least one heating element only when the liquidis present in the at least one channel.
 2. The vaporizer according toclaim 1, wherein each electrical contact of the pair of electricalcontacts is located in a respective wall of the at least one channel. 3.The vaporizer according to claim 2, wherein the electrical contacts arepositioned at an end of the at least one channel.
 4. The vaporizeraccording to claim 1, wherein the at least one channel is open in adirection perpendicular to a capillary flow direction within the atleast one channel.
 5. The vaporizer according to claim 1, wherein the atleast one channel is a microfluidic channel and wherein the absorbingstructure comprises a plurality of microfluidic channels.
 6. Thevaporizer according to claim 5, wherein the microfluidic channel of eachof the at least one channel are formed is defined by a network ofchannel structures.
 7. The vaporizer according to claim 6, wherein themicrofluidic channel of each of the at least one channel comprises aplurality of protrusions.
 8. The vaporizer according to any one of thepreceding claim 1, wherein the absorbing structure is a planar substrateon which the at least one channel and the at least one heating elementare arranged.
 9. The vaporizer according to claim 1, wherein thevaporizer further comprising a supply conduit configured to connect to aliquid transfer element and draw the liquid by capillary action into theat least one channel.
 10. The vaporizer according to claim 9, whereinthe absorbing structure is divided into a plurality of segments, andwherein each segment of the plurality of segments comprises a respectivechannel of the at least one channel thermally coupled to a respectiveheating element of the at least one heating element, and wherein each ofthe channels has a first end connected to the supply conduit.
 11. Thevaporizer according to claim 10, wherein only a single channel isdefined in each segment of the absorbing surface structure.
 12. Thevaporizer according to any one of the preceding claim 1, wherein the atleast one channel has an elongated structure.
 13. An electroniccigarette comprising the vaporizer according to claim 1, wherein theelectronic cigarette further comprises the power supply unit and theelectrical control circuitry, wherein at least a first channel of the atleast one channel is thermally coupled to a respective at least a firstheating element of the at least one heating element, and wherein the atleast a first heating element is controllable by the electrical controlcircuitry such that the power is supplied from the power supply unit tothe at least a first heating element only when the liquid is present inthe at least a first channel to which the respective at least a firstheating element is thermally coupled.
 14. The electronic cigaretteaccording to claim 13, wherein the electrical control circuitry furthercomprises at least one switch, wherein each of the at least one switchis configured to sense whether the liquid is present in a correspondingchannel of the at least one channel and to selectively activate arespective one of the at least one heating element thermally coupled tothat corresponding channel.
 15. The electronic cigarette according toclaim 14, wherein each of the at least one switch is configured to sensea change in capacitance or resistance due to an amount of the liquidpresent in the corresponding channel in order to determine that theliquid is present in the corresponding channel.
 16. The electroniccigarette according to claim 15, wherein the vaporizer comprises aplurality of the at least one channel and a plurality of the at leastone heating element, and wherein each of the plurality of heatingelements is individually controllable by the electrical controlcircuitry.
 17. The vaporizer according to claim 2, wherein eachelectrical contact of the pair of electrical contacts is located onopposing sides of the at least one channel in a horizontal plane. 18.The vaporizer according to claim 12, wherein the at least one channelfollows a serpentine path.